Glycols, especially triethylene glycol, are commonly used to absorb moisture from natural gas. After absorbing water by contacting the gas, the glycol solutions are usually regenerated by heating them to evaporate the water; the glycol solution, restored to its original strength, is then returned to the water absorption unit to absorb more moisture in a more or less continuous process.
Inevitably, the environment is exposed to the glycol solutions used in gas dehydration. Glycols are generally environmentally undesirable. An article at pages 59-79 of Chapter 6, Section 2 of the Engineering Data Books of the Gas Producers Society of America, entitled “Glycol Dehydration”, describes a typical gas drying and solution regeneration system, and some of the problems that can arise with such systems. Such a prior art gas drying and glycol regeneration system is shown in FIG. 1 hereof in a simplified form.
Atkinson, in U.S. Pat. No. 5,846,450, suggests the use of a potassium formate solution as a vapor absorbent in refrigeration, air conditioning, and dehumidifying systems. Potassium formate is an environmentally acceptable gas drying medium, but a more convenient and efficient method of regenerating solutions of potassium formate and other liquid absorbents would be highly beneficial for its commercial use.